The present invention generally relates to RF MEMS switches and, more particularly, to a RF MEMS switch that provides lower loss and better performance in K-band and further provides a method of fabrication of the RF MEMS package with all components on a single wafer without the need for external wires.
Integrated circuit (IC) packaging and testing has evolved over the past years due to the maturity of the IC industry, the availability of highly advanced infrastructure, and the wide applicability of the integrated circuits. In general, the goal for IC packaging is to provide an electrical interface to active chips in the system, to supply signal power and ground interconnections, to facilitate heat dissipation, and to at least partially protect the chips from the environment.
On the other hand, the requirements of micro electro mechanical systems (MEMS) packaging are different from those of IC packaging in that MEMS packaging requirements are application specific and, thus, different designs are used for different circuits. This lack of standardization leads to excessive cost associated with MEMS products.
Similarly, millimeter wave systems for commercial, scientific, or military applications are rapidly emerging that require development of packaging technologies that are capable of shielding high radio frequencies. For example, the performance requirements for high-density, high frequency (i.e. 5-100 GHz) packages are very stringent, since poor design and fabrication can lead to increased cavity resonances and cross-talk between neighboring circuits. Although many low cost materials can be utilized for packaging, such as plastic and alumina, these materials typically suffer from poor electrical performance at frequencies beyond 10 GHz.
Silicon on the other hand has been extensively used and studied in the electronics industry. Its electrical properties have enabled the semiconductor industry to use it as the primary dielectric material in developing integrated circuits, while its mechanical properties have been utilized to develop high performance micro-electro-mechanical system (MEMS) structures.
According to the teachings of the present invention, an RF micro-electro-mechanical system is provided having an advantageous construction. The RF MEMS system includes a first silicon wafer having a top surface and a bottom surface. The top surface is opposite the bottom surface. A bore extends through the first silicon wafer. A micro-electro-mechanical device is provided and coupled to the top surface of the first silicon wafer. An electrical feed line then extends along the bottom surface of the first silicon wafer and an electrical interconnect electrically couples the micro-electro-mechanical device and the electrical feed line through the bore.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.